1. Field of the Invention
The present invention relates to a generator control system, a generator control method, a power control system, a power control method, a program and a record medium of matching an electric load of household electrical appliances to an output of a generator.
2. Related Art of the Invention
On introducing a fuel battery or generators such as those using a gas engine and a gas turbine to a household, what should be considered is a scale of electric load fluctuation in a general household. In these generators, improvement in total energy utilization efficiency can be expected when effectively using waste heat together with a generating capacity. However, these generators take a long time from a start until reaching a desired output, and does not follow suitably the load fluctuation of household electrical appliances used in the general household.
As a method of following the electric load fluctuation of an electric power unit such as an air conditioner under such circumstances, a command value is conventionally outputted to the generator for the sake of following the electric load fluctuation based on the electric load fluctuation of the electric power unit before issuing an output control command to the generator. In the case of this method, for instance, there is a change in control over the electric power unit exerted by a user which appears as the load fluctuation, and the change is determined not to be temporary and then output control is finally exerted on the generator side based on the load fluctuation (refer to Japanese Patent Laid-Open No. 2002-319419 for instance).
As in the conventional example, in the case of determining an output of the generator from the electric load fluctuation of the household up to this time and operating the generator to simply follow it, it is finally reflected as a response command after the electric load starts fluctuation so that there will be a delay in responsiveness as the response command to the electric load fluctuation. Therefore, a shortage of the output arises in the case where the electric load is on the increase, and so there is a problem that commercial power is bought from a power company each time and there is no cost merit.
In the case of turning off an apparatus consuming a large amount of power such as the air conditioner, it is impossible, in the conventional example in which a response command is issued after the electric load starts fluctuation, to immediately issue the output control command thereto to control the output of the generator to follow the electric load fluctuation and there is a problem that surplus power is generated. There are two means of effectively using the surplus power.
The first means is to sell the surplus power to an outside power company (electric power selling). In this case, there is a problem that there is no guarantee of a unit price of the surplus power accepted by the outside power company being equal to or more than a generation cost of the generator, and so the more power is sold, the more money is lost. The second means is to store the surplus power in an accumulator and stagger utilization time. However, there is a problem that introduction of the accumulator requires a significant amount of initial cost and the introduction thereof to the general household is not realistic.
In the case of operating the generator to follow heat load fluctuation of the household, there is a problem that the generating capacity is not completely used and the surplus power is generated likewise.
To cope with the problem of the responsiveness as the response command to the electric load fluctuation, there is another conventional method of estimating current electric load fluctuation of the household electrical appliances from past data thereon and operating the generator based on estimation results (refer to Japanese Patent Laid-Open No. 2003-134888 for instance).
However, it is difficult for the conventional method as described in the above reference as Japanese Patent Laid-open No. 2003-134888 to correctly estimate electric load fluctuation of household electrical appliances since it is caused by irregular and unscheduled activities of persons handling them.
And since the generator such as a fuel battery does not have the good generation follow-up performance with regard to the load fluctuation of household electrical appliances used in the general household as described above, even if the electric load is correctly estimated, it is not possible after all to deal with the load fluctuation exceeding generation follow-up performance of the generator so that this method does not lead to a cost merit as explained as follows.
Specifically, FIG. 6 is an example of an air conditioner. Although how it starts is different from apparatus to apparatus, maximum power/rated power of the air conditioner when air-conditioning a room is 690 W/350 W for a 2.2 kW type, 780/420 W for a 2.5 kW type, and 900/475 W for a 2.8 kW type. FIG. 6 shows a power consumption trend of the 2.5 kW type on a startup. As can be seen from FIG. 6, a current air conditioner can start in as early as one minute.
For instance, load response performance of the fuel battery as the generator is 1 W/s for both output rise and fall according to a current target specification. It takes 5 minutes to increase its output to 300 W and 10 minutes in the case of increasing it to 600 W, and as a result, it is not possible after all to deal with the load fluctuation exceeding generation follow-up performance of the generator even if the electric load is correctly estimated expecting the load fluctuation as described above.
The present invention solves the problems of a representative method of following an electric load of a conventional generator control system described in the patent document, and an object thereof is to provide a generator control system, a generator control method, a program and a record medium excellent in responsiveness as a response command to the electric load fluctuation of the household electrical appliances and capable of outputting a command value by estimating an electric load value more accurately so as not to purchase relatively expensive commercial power from a power company when possible.
The present invention solves the problems of response performance substantially belonging to such a conventional generator, and another object thereof is to provide the generator control system of exerting control so that the electric load of the household electrical appliances substantially corresponds to output of the generator.
Further, the present invention also provides a power control system, a power control method, a program and a record medium of controlling apparatuses to effectively use surplus power for the apparatuses in a household without selling it to an outside power company when possible.